iOS打电话，发短信，发邮件，打开网址

    //调用自带mail
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto://admin@hzlzh.com"]];

    //调用电话
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel://8008808888"]];

    //调用sms
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"sms://800888"]];

    //调用打开网址
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"http://www.baidu.com"]];

调用phone可以传递号码，调用SMS 只能设定号码，不能初始化SMS内容。

发短信邮件需要的框架

导入头文件#import <MessageUI/MessageUI.h>

协议：<MFMailComposeViewControllerDelegate,MFMessageComposeViewControllerDelegate>

//点击按钮后，触发这个方法
-(void)sendEMail
{
    MFMailComposeViewController *mailPicker = [[MFMailComposeViewController alloc] init];

    mailPicker.mailComposeDelegate = self;

    //设置主题
    [mailPicker setSubject: @"eMail主题"];

    // 添加发送者
    NSArray *toRecipients = [NSArray arrayWithObject: @"first@example.com"];

    [mailPicker setToRecipients: toRecipients];

    // 添加图片
    UIImage *addPic = [UIImage imageNamed: @"ios.jpg"];
    NSData *imageData = UIImagePNGRepresentation(addPic);            // png
    // NSData *imageData = UIImageJPEGRepresentation(addPic, 1);    // jpeg
    [mailPicker addAttachmentData: imageData mimeType: @"" fileName: @"ios.jpg"];

    NSString *emailBody = @"eMail 正文";
    [mailPicker setMessageBody:emailBody isHTML:YES];

    [self presentViewController:mailPicker animated:YES completion:nil];
}

- (void)sendSMS{
    MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];

    if([MFMessageComposeViewController canSendText])
    {
        controller.body = @"";
        controller.recipients = @[@"",@""];
        controller.messageComposeDelegate = self;

        [self presentViewController:controller animated:YES completion:nil];
    }
}

#pragma mark - <MFMessageComposeViewControllerDelegate>

// 处理发送完的响应结果
- (void)messageComposeViewController:(MFMessageComposeViewController *)controller didFinishWithResult:(MessageComposeResult)result
{
    [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];

    if (result == MessageComposeResultCancelled){
        NSLog(@"Message cancelled");
    }

    else if (result == MessageComposeResultSent){
        NSLog(@"Message sent");
    }

    else{
        NSLog(@"Message failed");
    }
}

#pragma mark - <MFMailComposeViewControllerDelegate>

- (void)mailComposeController:(MFMailComposeViewController *)controller
          didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error
{
    NSString *msg;

    switch (result)
    {
        case MFMailComposeResultCancelled:
            msg = @"邮件发送取消";
            break;
        case MFMailComposeResultSaved:
            msg = @"邮件保存成功";

            break;
        case MFMailComposeResultSent:
            msg = @"邮件发送成功";

            break;
        case MFMailComposeResultFailed:
            msg = @"邮件发送失败";

            break;
        default:
            break;
    }
    [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}